Children in the United States are severely exposed to violence and pornography, which are mainly from their families and schools, the State Council Information Office of the People's Republic of China said in a report on Friday.

The statement was made in the office's Human Rights Record of the United States in 2011 that was released Friday in response to a Thursday U.S. assessment of human rights in other countries, in which it says human rights are deteriorating in China.

More than 20,000 American children were believed to have been killed by their family members, according to examples cited by the report. Over 1 million children become victims of child abuse every year, and one of every two families in the United States is involved in domestic violence.

Campus violence and cyber bullying are growing more malicious in the United States, with at least 40 percent of high school students having been bullied by cyber bullies, said the report.

The sex-trafficking problem is also acute in the United States. The report cited the state of Georgia for example, saying an estimated 250 to 300 underage teens and girls being sexually exploited each month there.

According to a report published by the Stanford University, the number of reports of sexual assaults received in its campus in 2010 rose by 75 percent over that in 2009, it said.